High Tech Pet brings you the latest innovation in pet doors. Our new, Armor Flex premium aluminum pet doors are the best sealed, most secure, most energy efficient and best built pet doors on the market. These superior pet doors feature our new, patent pending, flap design made of interlocking segments that provide horizontal rigidity to fully compress seals on the sides of the flap, while providing vertical flexibility so your pet can easily and safely pass through the opening. There is no other pet door like it on Earth. The frame features industrial grade, heavy gauge aluminum construction. The flap is constructed from a super high strength ABS composite. Air tight sealing is accomplished by a matrix of rare earth magnets to individually align each flap segment to compress the seals. This unique magnetic, segmented flap design will withstand storm force winds while easily allowing a pet to push it open. Armor Flex doors are finished with an extremely tough powder coating to resist scratches, wear and tear and will remain beautiful for years and years. These doors are truly built to last a lifetime. The AF2 is our doorl mount model. Small (AF2-S) is for dogs up to 25 lbs. and up to 12″ tall; Medium (AF2-M) is for dogs from 25 to 50 lbs. up to 20″ tall; Large (AF2-L) is for dogs 50 to 90 lbs. up to 24″ tall; X-Large (AF2-XL) is for dogs from 90 to 150 lbs. and over 25″ tall. Note: For wall mount model, please order Armor Flex Door, Model AF2-W. NOTE: Please see size chart in images provided.